Method and system for seat belt retraction speed control
AssigneeVolvo Car Corporation
InventorsPeter Adolfsson, Gert Aldeborg
Life of this patent
Estimating the term…
Abstract
A seat belt is wound around a spool and a spring biases the spool to rotate in a belt retraction direction. A sensor detects a retraction speed of the belt when the spool rotates in the belt retraction direction and generating a belt speed signal. An electrical drive unit receives the belt speed signal and applies a torque to the spool in a belt extension direction (opposite to the belt retraction direction) if the retraction speed exceeds a threshold value. The torque is of a magnitude sufficient to maintain the retraction speed below the threshold value. The electric motor and/or electrical control unit may be part of or otherwise integrated with a safety belt pre-tensioning system.
Claims19
A method for controlling a retraction speed of a seat belt wound around a spool, the spool rotatable in a belt extension direction and in an opposite belt retraction direction, the method comprising:
- applying, by means of a biasing arrangement, a first torque rotating the spool in the belt retraction direction monitoring the retraction speed of the seat belt;
- and
- if the retraction speed exceeds a predetermined threshold value, activating an electric motor to apply a second torque to the spool in the belt extension direction to limit the retraction speed.
Apparatus for extending and retracting a seat belt comprising:
- a spool around which the seat belt is wound, the spool rotatable in a belt extension direction and in an opposite belt retraction direction;-a spring biasing the spool in the belt retraction direction;-a sensor detecting a refraction speed of the belt when the spool rotates in the belt refraction direction and generating a belt speed signal;
- and -an electrical drive unit receiving the belt speed signal and applying a torque to the spool in the belt extension direction if the retraction speed exceeds a threshold value, the torque sufficient to maintain the retraction speed below the threshold value.
Apparatus for limiting a rotational speed of a spool around which a seat belt is wound, the spool biased by a spring mechanism to rotate in a belt retraction direction, the apparatus comprising:
- a sensor detecting the rotational speed of the spool in the belt retraction direction;
- an electrical control unit receiving an indication of the rotational speed from the sensor;
- and an electric motor controlled by the electrical control unit to apply a torque to the spool counter to the belt retraction direction if the rotational speed exceeds a threshold value, the torque sufficient to maintain the rotational speed below the threshold value.
Dependencies are inferred from the claim text.